Low Fat chicken enchalada casserole! NOT My recipe... from a website

1 large onion, chopped
1 medium green pepper, chopped
1 teaspoon butter
3 cups shredded cooked chicken breast
2 cans (4 ounces each) chopped green chilies
1/4 cup all-purpose flour
1-1/2 to 2 teaspoons ground coriander ( i used a Chipotle or chile spice not coriander)
2-1/2 cups reduced-sodium chicken broth
1 cup (8 ounces) reduced-fat sour cream
1 cup (4 ounces) reduced-fat Monterey Jack or reduced-fat Mexican cheese blend, divided
12 corn tortillas (6 inches), warmed
Serve with salsa and might need some salt..... This would be really good full fat but still good low fat too!
Directions

In a small skillet, saute onion and green pepper in butter until tender. In a large bowl, combine the chicken, green chilies and onion mixture.
In a small saucepan, combine flour and coriander. Add broth; stir until smooth. Cook and stir over medium heat until mixture comes to a boil. Cook and stir 1-2 minutes longer or until thickened. Remove from the heat; stir in sour cream and 1/2 cup cheese. Stir 3/4 cup sauce into chicken mixture.
Place 1/3 cup chicken mixture down the center of each tortilla. Roll up and place seam side down in a 13-in. x 9-in. baking dish coated with cooking spray. Pour remaining sauce over top; sprinkle with remaining cheese. Bake, uncovered, at 350° for 30-35 minutes or until heated through. Yield: 6 servings.